Why Does Toilet Water Move When It's Windy Outside?

iStock/kanjana intaounwong
iStock/kanjana intaounwong

Reader Erin from Baltimore wrote in wondering why the water in her toilet bowl moves on windy days. This is one of those questions – like the one Jason asked about his dog’s popcorn-scented paws – that makes me pause and wonder if I’m getting trolled, or if I’m missing out on a strange phenomena that everyone else seems to be aware of.

So, I did a little Googling and even hung out in the bathroom staring at the toilet bowl one morning (yes, folks, this is the exciting life of a science writer). Turns out Erin isn’t messing with me. Perhaps I'm one of the last people on Earth to realize toilet water moves with the breeze. Way to go, Soniak.

So, what causes this commotion in the latrine?

In many homes (at least in the U.S.), part of the plumbing system is a pipe that runs up and out to the roof. This outlet, called a “vent stack,” allows sewage gases to vent outside instead of through the toilet, sink or tub—which would make the house reek. The stack also allows air to move through the pipes, which makes wastewater drain smoothly and keeps obnoxious gurgling to a minimum.

When the wind blows over the vent stack outlet on the roof, the air pressure in the pipe is lowered. This is Bernoulli’s principle (“as the speed of a moving fluid increases, the pressure within the fluid decreases”), the same thing that gives airplanes their lift, in action in your bathroom. The lowered pressure in the pipes creates a slight suction effect throughout the plumbing system, pulling on water in the toilet below. As the wind kicks up and dies down, the suction gets stronger and weaker, and the water in the bowl sloshes around accordingly.

Wayfair’s Fourth of July Clearance Sale Takes Up to 60 Percent Off Grills and Outdoor Furniture

Wayfair/Weber
Wayfair/Weber

This Fourth of July, Wayfair is making sure you can turn your backyard into an oasis while keeping your bank account intact with a clearance sale that features savings of up to 60 percent on essentials like chairs, hammocks, games, and grills. Take a look at some of the highlights below.

Outdoor Furniture

Brisbane bench from Wayfair
Brisbane/Wayfair

- Jericho 9-Foot Market Umbrella $92 (Save 15 percent)
- Woodstock Patio Chairs (Set of Two) $310 (Save 54 percent)
- Brisbane Wooden Storage Bench $243 (Save 62 percent)
- Kordell Nine-Piece Rattan Sectional Seating Group with Cushions $1800 (Save 27 percent)
- Nelsonville 12-Piece Multiple Chairs Seating Group $1860 (Save 56 percent)
- Collingswood Three-Piece Seating Group with Cushions $410 (Save 33 percent)

Grills and Accessories

Dyna-Glo electric smoker.
Dyna-Glo/Wayfair

- Spirit® II E-310 Gas Grill $479 (Save 17 percent)
- Portable Three-Burner Propane Gas Grill $104 (Save 20 percent)
- Digital Bluetooth Electric Smoker $224 (Save 25 percent)
- Cuisinart Grilling Tool Set $38 (Save 5 percent)

Outdoor games

American flag cornhole game.
GoSports

- American Flag Cornhole Board $57 (Save 19 percent)
- Giant Four in a Row Game $30 (Save 6 percent)
- Giant Jenga Game $119 (Save 30 percent)

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Map Shows How Everyone Blamed Syphilis on Everyone Else

Portrait of Gerard de Lairesse by Rembrandt van Rijn. De Lairesse, a painter and art theorist, had congenital syphilis that deformed his face and eventually blinded him.
Portrait of Gerard de Lairesse by Rembrandt van Rijn. De Lairesse, a painter and art theorist, had congenital syphilis that deformed his face and eventually blinded him.
Gerard de Lairesse, Wikimedia Commons // Public Domain

The origins of syphilis may be one of the greatest (and grossest) health mysteries of our time. Some historians claim that Christopher Columbus and his sailors contracted the sexually transmitted disease in the New World and brought it back to Europe. Other experts believe that the disease, which is caused by the bacterium Treponema pallidum, existed in various forms around the globe but was simply misclassified as other conditions. (European writers, including Italian historian Niccolo Squillaci, first described syphilis in the late 15th century.) And in 2015, researchers announced that they had identified signs of congenital syphilis in 14th-century skeletons from St. Polten, Austria, adding new evidence to an ages-old debate.

One thing's for sure: As the map below illustrates, nobody wanted to take credit for originating the virulent condition. Created by Redditor masiakasaurus (and spotted by The A.V. Club), the map illustrates the various nicknames Europeans gave the disease before the name syphilis caught on. (Italian physician and poet Hieronymus Fracastorius coined the word in 1530 with his poem "Syphilis Sive Morbus Gallicus" ("Syphilis or the French Disease"). Not surprisingly, nearly every single moniker used for the disease places blame on another group for giving birth to what by then had become a continental scourge.

“Most physicians felt that this was a new disease, that it hadn’t been seen before in Europe, and that view tended to prevail for quite some time,” medical historian John Parascandola told The Atlantic in 2016. “There were certain tempting reasons for people to accept that—blame it on the others, blame it on the outsiders. Before that, the French were blaming it on the Italians, the Italians were blaming it on the French, et cetera.”

Masiakasaurus sourced the syphilis nicknames from nine scholarly books/journals, including The Early History of Syphilis: A Reappraisal,The rise and fall of sexually transmitted diseases in Sweden, and A Medical History of Persia and the Eastern Caliphate: From the Earliest Times Until the Year A.D. 1932. You can view the full list on Reddit—after giving silent thanks to Alexander Fleming for discovering penicillin, found to be an effective cure for syphilis in 1943.

[h/t The A.V. Club]